Optical lens system with a wide field of view

ABSTRACT

An optical lens system with a wide field of view includes, in order from the object side to the image side: a stop, a first lens element with a negative refractive power, a second lens element with a positive refractive power, a third lens element with a negative refractive power, a fourth lens element with a positive refractive power, and a fifth lens element with a negative refractive power. Such arrangements can provide a five-piece optical lens system which has a wide field of view, high resolution, short length and less distortion.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to an optical lens system with a widefield of view, and more particularly to a miniaturized five-pieceoptical lens system with a wide field of view which is applicable toelectronic products.

Description of the Prior Art

In recent years, with the popularity of electronic products with thefunction of taking photographs, there's an increasing demand for anoptical lens system. In order to obtain a wider shooting range, the lensangle should meet certain requirements. The field of view of the lens isusually designed to be 50 to 60 degrees, if over the above design angle,the aberration is larger and the lens design is more complex. Forexample, the optical lens systems as disclosed in U.S. Pat. Nos.8,335,043 and 8,576,497 use two lens groups and 5-6 pieces of lenselements to obtain a wide field of view, however, their distortion isincreased. The optical lens systems as disclosed in U.S. Pat. Nos.8,593,737, 8,576,497 and 8,395,853 also have a wide field of view, buttheir TL (total length) of the entire optical lens system is too long.

Therefore, how to develop a miniaturized optical lens system with a widefield of view which not only can be applied to lenses of the electronicproducts, such as, digital camera, Webcam, mobile phone and so on, butalso can reduce the aberration and the design complexity is themotivation of the present invention.

The present invention mitigates and/or obviates the aforementioneddisadvantages.

SUMMARY OF THE INVENTION

The primary objective of the present invention is to provide afive-piece optical lens system which has a wide field of view, highresolution, short length and less distortion.

Therefore, an optical lens system with a wide field of view inaccordance with the present invention comprises, in order from an objectside to an image side: a stop; a first lens element with a negativerefractive power, having an object-side surface being convex near anoptical axis and an image-side surface being concave near the opticalaxis, at least one of the object-side surface and the image-side surfaceof the first lens element being aspheric; a second lens element with apositive refractive power, having an object-side surface being convexnear the optical axis and an image-side surface being convex near theoptical axis, at least one of the object-side surface and the image-sidesurface of the second lens element being aspheric; a third lens elementwith a negative refractive power having an image-side surface beingconcave near the optical axis, at least one of an object-side surfaceand the image-side surface of the third lens element being aspheric; afourth lens element with a positive refractive power having anobject-side surface being convex near the optical axis and an image-sidesurface being convex near the optical axis, at least one of theobject-side surface and the image-side surface of the fourth lenselement being aspheric; a fifth lens element with a negative refractivepower having an object-side surface being convex near the optical axisand an image-side surface being concave near the optical axis, at leastone of the object-side surface and the image-side surface of the fifthlens element being aspheric and provided with at least one inflectionpoint.

Preferably, a focal length of the first lens element is f1, a focallength of the second lens element is f2, and they satisfy the relation:−2.4<f1/f2<−0.8, so that the refractive power of the first lens elementand the second lens element are more suitable, it will be favorable toobtain a wide field of view and avoid the excessive increase ofaberration of the system.

Preferably, the focal length of the second lens element is f2, a focallength of the third lens element is f3, and they satisfy the relation:−1.1<f2/f3<−0.6, so that the refractive power of the second lens elementand the third lens element are more balanced, it will be favorable tocorrect the aberration of the system and reduce the sensitivity of thesystem.

Preferably, the focal length of the third lens element is f3, a focallength of the fourth lens element is f4, and they satisfy the relation:−1.8<f3/f4<−0.5, so that the telephoto structure formed by the positiveand negative third and fourth lens elements can effectively reduce thetotal length of the optical lens system.

Preferably, the focal length of the fourth lens element is f4, a focallength of the fifth lens element is f5, and they satisfy the relation:−0.8<f4/f5<−0.05, so that the refractive power of the rear group lenssystem is more balanced, it will be favorable to reduce the sensitivityof the system and correct the high order aberrations of the system.

Preferably, the focal length of the first lens element is f1, the focallength of the third lens element is f3, and they satisfy the relation:0.7<f1/f3<2.0, so that the refractive power of the first lens elementcan be distributed effectively, so as to reduce the sensitivity of theoptical lens system with a wide field of view.

Preferably, the focal length of the second lens element is f2, the focallength of the fourth lens element is f4, and they satisfy the relation:0.3<f2/f4<1.5, so that the distribution of the negative refractive powerwill be appropriate, it will be favorable to correct the aberration ofthe system and improve the image quality.

Preferably, the focal length of the third lens element is f3, the focallength of the fifth lens element is f5, and they satisfy the relation:0.05<f3/f5<1.0, it will be favorable to reduce the total length andfacilitates the miniaturization of the optical lens system with a widefield of view.

Preferably, the focal length of the first lens element is f1, a focallength of the second lens element and the third lens element combined isf23, and they satisfy the relation: −1.3<f1/f23<−0.25. If f1/f23satisfies the above relation, a wide field of view can be obtained andthe resolution can be improved evidently.

Preferably, the focal length of the second lens element and the thirdlens element combined is f23, a focal length of the fourth lens elementand the fifth lens element combined is f45, and they satisfy therelation: 0.6<f23/f45<3.6. If f23/f45 satisfies the above relation, awide field of view, high pixel and low height can be provided and theresolution can be improved evidently. Contrarily, if f23/f45 exceeds theabove range, the performance and resolution of the optical lens systemwith a wide field of view will be reduced, and the yield rate will below.

Preferably, a focal length of the first lens element and the second lenselement combined is f12, a focal length of the third lens element andthe fourth lens element combined is f34, and they satisfy the relation:−0.1<f12/f34<0.8, which is favorable to obtain a wide field of view, andeffectively correct image distortion.

Preferably, the focal length of the third lens element and the fourthlens element combined is f34, the focal length of the fifth lens elementis f5, and they satisfy the relation: −2.3<f34/f5<6.8. If f34/f5satisfies the above relation, a wide field of view, high pixel and lowheight can be provided and the resolution can be improved evidently.Contrarily, if f34/f5 exceeds the above range, the performance andresolution of the optical lens system with a wide field of view will bereduced, and the yield rate will be low.

Preferably, the focal length of the first lens element is f1, a focallength of the second lens element, the third lens element and the fourthlens element combined is f234, and they satisfy the relation:−2.2<f1/f234<−0.5. Appropriate refractive power is favorable to reducethe spherical aberration and astigmatism of the optical lens systemeffectively.

Preferably, the focal length of the second lens element, the third lenselement and the fourth lens element combined is f234, the focal lengthof the fifth lens element is f5, and they satisfy the relation:−0.9<f234/f5<−0.05. Appropriate refractive power is favorable to reducethe spherical aberration and astigmatism of the optical lens systemeffectively.

Preferably, the focal length of the first lens element, the second lenselement and the third lens element combined is f123, the focal length ofthe fourth lens element is f4, and they satisfy the relation:−4.9<f123/f4<4.5. Appropriate refractive power is favorable to reducethe spherical aberration and astigmatism of the optical lens systemeffectively.

Preferably, the focal length of the first lens element, the second lenselement and the third lens element combined is f123, the focal length ofthe fourth lens element and the fifth lens element combined is f45, andthey satisfy the relation: −5.1<f123/f45<3.5. Appropriate refractivepower is favorable to reduce the spherical aberration and astigmatism ofthe optical lens system effectively.

Preferably, the focal length of the first lens element is f1, a focallength of the second lens element, the third lens element, the fourthlens element and the fifth lens element combined is f2345, and theysatisfy the relation: −2.5<f1/f2345<−1.2. If f1/f2345 satisfies theabove relation, a wide field of view, high pixel and low height can beprovided and the resolution can be improved evidently. Contrarily, iff1/f2345 exceeds the above range, the performance and resolution of theoptical lens system with a wide field of view will be reduced, and theyield rate will be low.

Preferably, an Abbe number of the second lens element is V2, an Abbenumber of the third lens element is V3, and they satisfy the followingrelation: 29<V2−V3<42, which can reduce the chromatic aberration of theoptical lens system effectively.

Preferably, an Abbe number of the fourth lens element is V4, an Abbenumber of the fifth lens element is V5, and they satisfy the followingrelation: 29<V4−V5<42, which can reduce the chromatic aberration of theoptical lens system effectively.

Preferably, a focal length of the optical lens system with a wide fieldof view is f, a distance from the object-side surface of the first lenselement to the image plane along the optical axis is TL, and theysatisfy the relation: 0.05<f/TL<0.4, it will be favorable to obtain awide field of view and maintain the objective of miniaturization of theoptical lens system, which can be used in thin electronic products.

The present invention will be presented in further details from thefollowing descriptions with the accompanying drawings, which show, forpurpose of illustrations only, the preferred embodiments in accordancewith the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A shows an optical lens system with a wide field of view inaccordance with a first embodiment of the present invention;

FIG. 1B shows the image plane curve and the distortion curve of thefirst embodiment of the present invention;

FIG. 2A shows an optical lens system with a wide field of view inaccordance with a second embodiment of the present invention;

FIG. 2B shows the image plane curve and the distortion curve of thesecond embodiment of the present invention;

FIG. 3A shows an optical lens system with a wide field of view inaccordance with a third embodiment of the present invention; and

FIG. 3B shows the image plane curve and the distortion curve of thethird embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to FIGS. 1A and 1B, FIG. 1A shows an optical lens system witha wide field of view in accordance with a first embodiment of thepresent invention, and FIG. 1B shows, in order from left to right, theimage plane curve and the distortion curve of the first embodiment ofthe present invention. An optical lens system with a wide field of viewin accordance with the first embodiment of the present inventioncomprises a stop 100 and a lens group. The lens group comprises, inorder from an object side to an image side: a first lens element 110, asecond lens element 120, a third lens element 130, a fourth lens element140, a fifth lens element 150, an IR cut filter 170, and an image plane180, wherein the optical lens system with a wide field of view has atotal of five lens elements with refractive power. The stop 100 isdisposed between an image-side surface 112 of the first lens element 110and an image-side surface 122 of the second lens element 120.

The first lens element 110 with a negative refractive power has anobject-side surface 111 being convex near an optical axis 190 and theimage-side surface 112 being concave near the optical axis 190, theobject-side surface 111 and the image-side surface 112 are aspheric, andthe first lens element 110 is made of plastic material.

The second lens element 120 with a positive refractive power has anobject-side surface 121 being convex near the optical axis 190 and theimage-side surface 122 being convex near the optical axis 190, theobject-side surface 121 and the image-side surface 122 are aspheric, andthe second lens element 120 is made of plastic material.

The third lens element 130 with a negative refractive power has anobject-side surface 131 being concave near the optical axis 190 and animage-side surface 132 being concave near the optical axis 190, theobject-side surface 131 and the image-side surface 132 are aspheric, andthe third lens element 130 is made of plastic material.

The fourth lens element 140 with a positive refractive power has anobject-side surface 141 being convex near the optical axis 190 and animage-side surface 142 being convex near the optical axis 190, theobject-side surface 141 and the image-side surface 142 are aspheric, andthe fourth lens element 140 is made of plastic material.

The fifth lens element 150 with a negative refractive power has anobject-side surface 151 being convex near the optical axis 190 and animage-side surface 152 being concave near the optical axis 190, theobject-side surface 151 and the image-side surface 152 are aspheric, thefifth lens element 150 is made of plastic material, and at least one ofthe object-side surface 151 and the image-side surface 152 is providedwith at least one inflection point.

The IR cut filter 170 made of glass is located between the fifth lenselement 150 and the image plane 180 and has no influence on the focallength of the optical lens system with a wide field of view.

The equation for the aspheric surface profiles of the respective lenselements of the first embodiment is expressed as follows:

$z = {\frac{{ch}^{2}}{1 + \left\lbrack {1 - {\left( {k + 1} \right)c^{2}h^{2}}} \right\rbrack^{0.5}} + {Ah}^{4} + {Bh}^{6} + {Ch}^{8} + {Dh}^{10} + {Eh}^{12} + {Gh}^{14} + \ldots}$

wherein:

z represents the value of a reference position with respect to a vertexof the surface of a lens and a position with a height h along theoptical axis 190;

c represents a paraxial curvature equal to 1/R (R: a paraxial radius ofcurvature);

h represents a vertical distance from the point on the curve of theaspheric surface to the optical axis 190;

k represents the conic constant;

A, B, C, D, E, G, . . . : represent the high-order asphericcoefficients.

In the first embodiment of the present optical lens system with a widefield of view, a focal length of the optical lens system with a widefield of view is f, a f-number of the optical lens system with a widefield of view is Fno, the optical lens system with a wide field of viewhas a maximum view angle (field of view) FOV, and they satisfy therelations: f=1.12 mm; Fno=2.4; and FOV=111 degrees.

In the first embodiment of the present optical lens system with a widefield of view, a focal length of the first lens element 110 is f1, afocal length of the second lens element 120 is f2, and they satisfy therelation: f1/f2=−1.77.

In the first embodiment of the present optical lens system with a widefield of view, the focal length of the second lens element 120 is f2, afocal length of the third lens element 130 is f3, and they satisfy therelation: f2/f3=−0.82.

In the first embodiment of the present optical lens system with a widefield of view, the focal length of the third lens element 130 is f3, afocal length of the fourth lens element 140 is f4, and they satisfy therelation: f3/f4=−0.70.

In the first embodiment of the present optical lens system with a widefield of view, the focal length of the fourth lens element 140 is f4, afocal length of the fifth lens element 150 is f5, and they satisfy therelation: f4/f5=−0.49.

In the first embodiment of the present optical lens system with a widefield of view, the focal length of the first lens element 110 is f1, thefocal length of the third lens element 130 is f3, and they satisfy therelation: f1/f3=1.45.

In the first embodiment of the present optical lens system with a widefield of view, the focal length of the second lens element 120 is f2,the focal length of the fourth lens element 140 is f4, and they satisfythe relation: f2/f4=0.58.

In the first embodiment of the present optical lens system with a widefield of view, the focal length of the third lens element 130 is f3, thefocal length of the fifth lens element 150 is f5, and they satisfy therelation: f3/f5=0.34.

In the first embodiment of the present optical lens system with a widefield of view, the focal length of the first lens element 110 is f1, afocal length of the second lens element 120 and the third lens element130 combined is f23, and they satisfy the relation: f1/f23=−0.90.

In the first embodiment of the present optical lens system with a widefield of view, the focal length of the second lens element 120 and thethird lens element 130 combined is f23, a focal length of the fourthlens element 140 and the fifth lens element 150 combined is f45, andthey satisfy the relation: f23/f45=0.88.

In the first embodiment of the present optical lens system with a widefield of view, a focal length of the first lens element 110 and thesecond lens element 120 combined is f12, a focal length of the thirdlens element 130 and the fourth lens element 140 combined is f34, andthey satisfy the relation: f12/f34=−0.03.

In the first embodiment of the present optical lens system with a widefield of view, the focal length of the third lens element 130 and thefourth lens element 140 combined is f34, the focal length of the fifthlens element 150 is f5, and they satisfy the relation: f34/f5=6.47.

In the first embodiment of the present optical lens system with a widefield of view, the focal length of the first lens element 110 is f1, afocal length of the second lens element 120, the third lens element 130and the fourth lens element 140 combined is f234, and they satisfy therelation: f1/f234=−1.30.

In the first embodiment of the present optical lens system with a widefield of view, the focal length of the second lens element 120, thethird lens element 130 and the fourth lens element 140 combined is f234,the focal length of the fifth lens element 150 is f5, and they satisfythe relation: f234/f5=−0.38.

In the first embodiment of the present optical lens system with a widefield of view, a focal length of the first lens element 110, the secondlens element 120 and the third lens element 130 combined is f123, thefocal length of the fourth lens element 140 is f4, and they satisfy therelation: f123/f4=1.75.

In the first embodiment of the present optical lens system with a widefield of view, the focal length of the first lens element 110, thesecond lens element 120 and the third lens element 130 combined is f123,the focal length of the fourth lens element 140 and the fifth lenselement 150 combined is f45, and they satisfy the relation:f123/f45=1.35.

In the first embodiment of the present optical lens system with a widefield of view, the focal length of the first lens element 110 is f1, afocal length of the second lens element 120, the third lens element 130,the fourth lens element 140 and the fifth lens element 150 combined isf2345, and they satisfy the relation: f1/f2345=−1.44.

In the first embodiment of the present optical lens system with a widefield of view, an Abbe number of the second lens element 120 is V2, anAbbe number of the third lens element 130 is V3, and they satisfy therelation: V2−V3=33.60.

In the first embodiment of the present optical lens system with a widefield of view, an Abbe number of the fourth lens element 140 is V4, anAbbe number of the fifth lens element 150 is V5, and they satisfy therelation: V4−V5=33.60.

In the first embodiment of the present optical lens system with a widefield of view, a focal length of the optical lens system with a widefield of view is f, a distance from the object-side surface 111 of thefirst lens element 110 to the image plane 180 along the optical axis 190is TL, and they satisfy the relation: f/TL=0.6571.

The detailed optical data of the first embodiment is shown in table 1,and the aspheric surface data is shown in table 2.

TABLE 1 Embodiment 1 f(focal length) = 1.12 mm, Fno = 2.4, FOV = 111deg. Curvature Focal surface Radius Thickness Material Index Abbe #length 0 object infinity 300.000 1 infinity 0.000 2 Lens 1 69.188 (ASP)0.653 plastic 1.535 56.000 −2.024 3 1.065 (ASP) 1.791 4 stop infinity0.010 5 Lens 2 1.268 (ASP) 1.017 plastic 1.535 56.000 1.142 6 −0.853(ASP) 0.046 7 Lens 3 −1.801 (ASP) 0.316 plastic 1.642 22.400 −1.395 81.933 (ASP) 0.042 9 Lens 4 1.926 (ASP) 0.965 plastic 1.535 56.000 1.97910 −1.953 (ASP) 0.048 11 Lens 5 2.024 (ASP) 0.431 plastic 1.642 22.400−4.059 12 1.048 (ASP) 0.297 13 IR-filter infinity 0.210 glass 1.51764.167 — 14 infinity 0.300 15 Image infinity infinity plane

TABLE 2 Aspheric Coefficients surface 2 3 5 6 7 K:  2.4259E+02−3.4734E−01 −2.9136E+00 −5.5156E+00 −2.3576E+00 A:  6.0253E−02 9.2402E−02  4.8468E−02 −7.2766E−01 −3.2049E−01 B: −1.8290E−02 1.4165E−01 −6.4485E−03  2.1581E+00  1.1582E+00 C:  2.9770E−03−1.2175E−01 −2.8874E−01 −5.1120E+00 −2.5652E+00 D: −2.0734E−04 3.6467E−02 −9.9823E−01  3.5195E+00  1.7189E−01 surface 8 9 10 11 12 K:−2.4314E+01  1.1467E−01 −1.8722E+00 −2.8959E+01 −4.4879E+00 A:−1.4152E−02 −1.1820E−02 −5.7877E−02 −2.2387E−01 −2.2713E−01 B: 2.0760E−01 −1.2497E−01 −4.1638E−02 −5.0757E−01  2.3273E−02 C: 2.2991E−02  2.4505E−01 −1.5628E−01  2.4595E−01  4.3301E−02 D:−1.8744E−01 −1.6142E−01  8.1595E−02 −6.1202E−02 −1.5811E−02

The units of the radius of curvature, the thickness and the focal lengthin table 1 are expressed in mm, the surface numbers 0-15 represent thesurfaces sequentially arranged from the object-side to the image-sidealong the optical axis. In table 2, k represents the conic coefficientof the equation of the aspheric surface profiles, and A, B, C, D, E, F,G . . . : represent the high-order aspheric coefficients. The tablespresented below for each embodiment are the corresponding schematicparameter and image plane curves, and the definitions of the tables arethe same as Table 1 and Table 2 of the first embodiment. Therefore, anexplanation in this regard will not be provided again.

Referring to FIGS. 2A and 2B, FIG. 2A shows an optical lens system witha wide field of view in accordance with a second embodiment of thepresent invention, and FIG. 2B shows, in order from left to right, theimage plane curve and the distortion curve of the second embodiment ofthe present invention. An optical lens system with a wide field of viewin accordance with the second embodiment of the present inventioncomprises a stop 200 and a lens group. The lens group comprises, inorder from an object side to an image side: a first lens element 210, asecond lens element 220, a third lens element 230, a fourth lens element240, a fifth lens element 250, an IR cut filter 270, and an image plane280, wherein the optical lens system with a wide field of view has atotal of five lens elements with refractive power. The stop 200 isdisposed between an image-side surface 212 of the first lens element 210and an image-side surface 222 of the second lens element 220.

The first lens element 210 with a negative refractive power has anobject-side surface 211 being convex near an optical axis 290 and theimage-side surface 212 being concave near the optical axis 290, theobject-side surface 211 and the image-side surface 212 are aspheric, andthe first lens element 210 is made of plastic material.

The second lens element 220 with a positive refractive power has anobject-side surface 221 being convex near the optical axis 290 and theimage-side surface 222 being convex near the optical axis 290, theobject-side surface 221 and the image-side surface 222 are aspheric, andthe second lens element 220 is made of plastic material.

The third lens element 230 with a negative refractive power has anobject-side surface 231 being convex near the optical axis 290 and animage-side surface 232 being concave near the optical axis 290, theobject-side surface 231 and the image-side surface 232 are aspheric, andthe third lens element 230 is made of plastic material.

The fourth lens element 240 with a positive refractive power has anobject-side surface 241 being convex near the optical axis 290 and animage-side surface 242 being convex near the optical axis 290, theobject-side surface 241 and the image-side surface 242 are aspheric, andthe fourth lens element 240 is made of plastic material.

The fifth lens element 250 with a negative refractive power has anobject-side surface 251 being convex near the optical axis 290 and animage-side surface 252 being concave near the optical axis 290, theobject-side surface 251 and the image-side surface 252 are aspheric, thefifth lens element 250 is made of plastic material, and at least one ofthe object-side surface 251 and the image-side surface 252 is providedwith at least one inflection point.

The IR cut filter 270 made of glass is located between the fifth lenselement 250 and the image plane 280 and has no influence on the focallength of the optical lens system with a wide field of view.

The detailed optical data of the second embodiment is shown in table 3,and the aspheric surface data is shown in table 4.

TABLE 3 Embodiment 2 f(focal length) = 1.94 mm, Fno = 2.0, FOV = 102deg. Curvature Focal surface Radius Thickness Material Index Abbe #length 0 object infinity 600.000 1 infinity 0.000 2 Lens 1 34.020 (ASP)1.417 plastic 1.535 56.000 −4.182 3 2.039 (ASP) 2.440 4 stop infinity−0.084 5 Lens 2 2.217 (ASP) 1.223 plastic 1.535 56.000 2.047 6 −1.701(ASP) 0.070 7 Lens 3 25.519 (ASP) 0.550 plastic 1.642 22.400 −2.522 81.464 (ASP) 0.100 9 Lens 4 2.530 (ASP) 1.196 plastic 1.535 56.000 2.28410 −1.921 (ASP) 0.450 11 Lens 5 5.438 (ASP) 0.636 plastic 1.642 22.400−3.483 12 1.479 (ASP) 0.445 13 IR-filter infinity 0.300 glass 1.51764.167 — 14 infinity 0.111 15 Image infinity infinity plane

TABLE 4 Aspheric Coefficients surface 2 3 5 6 7 K:  8.6937E+01 5.3318E−01 −3.3316E+00 −9.0427E+00  4.3268E+02 A:  1.1081E−02 1.6980E−02  6.5503E−03 −1.6408E−01 −1.4330E−01 B: −9.0703E−04 7.7160E−03  3.2006E−02  2.3790E−01  2.1364E−01 C:  5.3830E−05−2.5358E−03 −9.4256E−02 −2.4601E−01 −2.1172E−01 D: −1.5796E−06 4.8084E−04  4.9132E−02  8.2860E−02  7.3539E−02 surface 8 9 10 11 12 K:−6.3541E+00 −2.4603E+00 −3.7005E+00 −1.8539E+02 −7.5660E+00 A:−4.3120E−02 −3.7491E−02 −4.4896E−03 −7.7700E−02 −4.1425E−02 B: 9.2213E−02  5.5661E−02  5.2627E−03 −3.8137E−02 −4.3596E−03 C:−6.3790E−02 −2.9240E−02  5.7798E−03  2.7406E−02  2.6745E−03 D: 1.7863E−02  6.1330E−03 −1.6245E−03 −6.4250E−03 −3.5508E−04

In the second embodiment, the equation of the aspheric surface profilesof the aforementioned lens elements is the same as the equation of thefirst embodiment. Also, the definitions of these parameters shown in thefollowing table are the same as those stated in the first embodimentwith corresponding values for the second embodiment, so an explanationin this regard will not be provided again.

Moreover, these parameters can be calculated from Table 3 and Table 4 asthe following values and satisfy the following conditions:

Embodiment 2 f[mm] 1.940 f23/f45 1.30 Fno 2.0 f12/f34 0.24 FOV[deg.] 102f34/f5 −2.05 f1/f2 −2.04 f1/f234 −1.88 f2/f3 −0.81 f234/f5 −0.64 f3/f4−1.10 f123/f4 4.27 f4/f5 −0.66 f123/f45 3.18 f1/f3 1.66 f1/f2345 −2.09f2/f4 0.90 V2-V3 33.60 f3/f5 0.72 V4-V5 33.60 f1/f23 −1.05 f/TL 0.22

Referring to FIGS. 3A and 3B, FIG. 3A shows an optical lens system witha wide field of view in accordance with a third embodiment of thepresent invention, and FIG. 3B shows, in order from left to right, theimage plane curve and the distortion curve of the third embodiment ofthe present invention. An optical lens system with a wide field of viewin accordance with the third embodiment of the present inventioncomprises a stop 300 and a lens group. The lens group comprises, inorder from an object side to an image side: a first lens element 310, asecond lens element 320, a third lens element 330, a fourth lens element340, a fifth lens element 350, an IR cut filter 370, and an image plane380, wherein the optical lens system with a wide field of view has atotal of five lens elements with refractive power. The stop 300 isdisposed between an image-side surface 312 of the first lens element 310and an image-side surface 322 of the second lens element 320.

The first lens element 310 with a negative refractive power has anobject-side surface 311 being convex near an optical axis 390 and theimage-side surface 312 being concave near the optical axis 390, theobject-side surface 311 and the image-side surface 312 are aspheric, andthe first lens element 310 is made of plastic material.

The second lens element 320 with a positive refractive power has anobject-side surface 321 being convex near the optical axis 390 and theimage-side surface 322 being convex near the optical axis 390, theobject-side surface 321 and the image-side surface 322 are aspheric, andthe second lens element 320 is made of plastic material.

The third lens element 330 with a negative refractive power has anobject-side surface 331 being convex near the optical axis 390 and animage-side surface 332 being concave near the optical axis 390, theobject-side surface 331 and the image-side surface 332 are aspheric, andthe third lens element 330 is made of plastic material.

The fourth lens element 340 with a positive refractive power has anobject-side surface 341 being convex near the optical axis 390 and animage-side surface 342 being convex near the optical axis 390, theobject-side surface 341 and the image-side surface 342 are aspheric, andthe fourth lens element 340 is made of plastic material.

The fifth lens element 350 with a negative refractive power has anobject-side surface 351 being convex near the optical axis 390 and animage-side surface 352 being concave near the optical axis 390, theobject-side surface 351 and the image-side surface 352 are aspheric, thefifth lens element 350 is made of plastic material, and at least one ofthe object-side surface 351 and the image-side surface 352 is providedwith at least one inflection point.

The IR cut filter 370 made of glass is located between the fifth lenselement 350 and the image plane 380 and has no influence on the focallength of the optical lens system with a wide field of view.

The detailed optical data of the third embodiment is shown in table 5,and the aspheric surface data is shown in table 6.

TABLE 5 Embodiment 3 f(focal length) = 1.10 mm, Fno = 1.5, FOV = 113deg. Curvature Focal surface Radius Thickness Material Index Abbe #length 0 object infinity 1000.000 1 infinity 0.000 2 Lens 1 83.089 (ASP)1.038 plastic 1.535 56.000 −2.427 3 1.255 (ASP) 1.805 4 stop infinity−0.053 5 Lens 2 1.904 (ASP) 0.944 plastic 1.535 56.000 1.971 6 −1.898(ASP) 0.031 7 Lens 3 83.407 (ASP) 0.362 plastic 1.635 23.900 −2.289 81.384 (ASP) 0.045 9 Lens 4 1.234 (ASP) 1.057 plastic 1.535 56.000 1.57110 −1.777 (ASP) 0.041 11 Lens 5 1.607 (ASP) 0.476 plastic 1.635 23.900−12.661 12 1.182 (ASP) 0.840 13 Image infinity infinity plane

TABLE 6 Aspheric Coefficients surface 2 3 5 6 7 K: −3.0321E+01−8.9602E−01 −3.4167E+00 −1.4805E+01 −8.0016E+01 A:  2.4940E−02 8.5580E−02 −2.0075E−02 −4.0271E−01 −3.4014E−01 B: −3.1448E−03 2.2102E−02 −1.0360E−01  8.1989E−01  9.9372E−01 C:  2.1954E−04 5.2223E−02  4.0479E−02 −1.1089E+00 −1.1392E+00 D: −7.8936E−06−2.8190E−02 −2.2978E−01  4.3120E−01  4.6808E−01 surface 8 9 10 11 12 K:−7.1567E+00 −4.3121E+00 −1.5929E+01 −1.6582E+00 −1.5138E+00 A:−4.2286E−01 −2.0440E−01 −1.2349E−01 −2.2598E−01 −3.1840E−01 B: 7.2443E−01  3.4884E−01  2.2593E−01 −1.0983E−01  1.2822E−01 C:−4.9917E−01 −2.4992E−01 −1.5204E−01  1.0302E−01 −5.2667E−02 D: 1.4578E−01  7.4028E−02  4.5422E−02 −5.7493E−02  8.0450E−03

In the third embodiment, the equation of the aspheric surface profilesof the aforementioned lens elements is the same as the equation of thefirst embodiment. Also, the definitions of these parameters shown in thefollowing table are the same as those stated in the first embodimentwith corresponding values for the third embodiment, so an explanation inthis regard will not be provided again.

Moreover, these parameters can be calculated from Table 5 and Table 6 asthe following values and satisfy the following conditions:

Embodiment 3 f[mm] 1.100 f23/f45 3.36 Fno 1.5 f12/f34 0.57 FOV[deg.] 113f34/f5 −0.26 f1/f2 −1.23 f1/f234 −0.73 f2/f3 −0.86 f234/f5 −0.13 f3/f4−1.46 f123/f4 −4.45 f4/f5 −0.12 f123/f45 −4.76 f1/f3 1.06 f1/f2345 −1.62f2/f4 1.25 V2-V3 32.10 f3/f5 0.18 V4-V5 32.10 f1/f23 −0.49 f/TL 0.17

In the present optical lens system with a wide field of view, the lenselements can be made of plastic or glass. If the lens elements are madeof plastic, the cost will be effectively reduced. If the lens elementsare made of glass, there is more freedom in distributing the refractivepower of the optical lens system with a wide field of view. Plastic lenselements can have aspheric surfaces, which allow more design parameterfreedom (than spherical surfaces), so as to reduce the aberration andthe number of the lens elements, as well as the total track length ofthe optical lens system with a wide field of view.

In the present optical lens system with a wide field of view, if theobject-side or the image-side surface of the lens elements withrefractive power is convex and the location of the convex surface is notdefined, the object-side or the image-side surface of the lens elementsnear the optical axis is convex. If the object-side or the image-sidesurface of the lens elements is concave and the location of the concavesurface is not defined, the object-side or the image-side surface of thelens elements near the optical axis is concave.

The optical lens system with a wide field of view of the presentinvention can be used in focusing optical systems and can obtain betterimage quality. The optical lens system with a wide field of view of thepresent invention can also be used in electronic imaging systems, suchas, 3D image capturing, digital camera, mobile device, digital flatpanel or vehicle camera.

While we have shown and described various embodiments in accordance withthe present invention, it should be clear to those skilled in the artthat further embodiments may be made without departing from the scope ofthe present invention.

What is claimed is:
 1. An optical lens system with a wide field of view, in order from an object side to an image side, comprising: a stop; a first lens element with a negative refractive power, having an object-side surface being convex near an optical axis and an image-side surface being concave near the optical axis, at least one of the object-side surface and the image-side surface of the first lens element being aspheric; a second lens element with a positive refractive power, having an object-side surface being convex near the optical axis and an image-side surface being convex near the optical axis, at least one of the object-side surface and the image-side surface of the second lens element being aspheric; and a third lens element with a negative refractive power, having an image-side surface being concave near the optical axis, at least one of an object-side surface and the image-side surface of the third lens element being aspheric; a fourth lens element with a positive refractive power, having an object-side surface being convex near the optical axis and an image-side surface being convex near the optical axis, at least one of the object-side surface and the image-side surface of the fourth lens element being aspheric; and a fifth lens element with a negative refractive power, having an object-side surface being convex near the optical axis and an image-side surface being concave near the optical axis, at least one of the object-side surface and the image-side surface of the fifth lens element being aspheric and provided with at least one inflection point; wherein a focal length of the second lens element is f2, a focal length of the fourth lens element is f4, and they satisfy the relation: 0.3<f2/f4<1.5.
 2. The optical lens system with a wide field of view as claimed in claim 1, wherein a focal length of the first lens element is f1, the focal length of the second lens element is f2, and they satisfy the relation: −2.4<f1/f2<−0.8.
 3. The optical lens system with a wide field of view as claimed in claim 1, wherein the focal length of the second lens element is f2, a focal length of the third lens element is f3, and they satisfy the relation: −1.1<f2/f3<−0.6.
 4. The optical lens system with a wide field of view as claimed in claim 1, wherein a focal length of the third lens element is f3, the focal length of the fourth lens element is f4, and they satisfy the relation: −1.8<f3/f4<−0.5.
 5. The optical lens system with a wide field of view as claimed in claim 1, wherein the focal length of the fourth lens element is f4, a focal length of the fifth lens element is f5, and they satisfy the relation: −0.8<f4/f5<−0.05.
 6. The optical lens system with a wide field of view as claimed in claim 1, wherein a focal length of the first lens element is f1, a focal length of the third lens element is f3, and they satisfy the relation: 0.7<f1/f3<2.0.
 7. The optical lens system with a wide field of view as claimed in claim 1, wherein a focal length of the third lens element is f3, a focal length of the fifth lens element is f5, and they satisfy the relation: 0.05<f3/f5<1.0.
 8. The optical lens system with a wide field of view as claimed in claim 1, wherein a focal length of the first lens element is f1, a focal length of the second lens element and the third lens element combined is f23, and they satisfy the relation: −1.3<f1/f23<−0.25.
 9. The optical lens system with a wide field of view as claimed in claim 1, wherein a focal length of the second lens element and the third lens element combined is f23, a focal length of the fourth lens element and the fifth lens element combined is f45, and they satisfy the relation: 0.6<f23/f45<3.6.
 10. The optical lens system with a wide field of view as claimed in claim 1, wherein a focal length of the first lens element and the second lens element combined is f12, a focal length of the third lens element and the fourth lens element combined is f34, and they satisfy the relation: −0.1<f12/f34<0.8.
 11. The optical lens system with a wide field of view as claimed in claim 1, wherein a focal length of the third lens element and the fourth lens element combined is f34, a focal length of the fifth lens element is f5, and they satisfy the relation: −2.3<f34/f5<6.8.
 12. The optical lens system with a wide field of view as claimed in claim 1, wherein a focal length of the first lens element is f1, a focal length of the second lens element, the third lens element and the fourth lens element combined is f234, and they satisfy the relation: −2.2<f1/f234<−0.5.
 13. The optical lens system with a wide field of view as claimed in claim 1, wherein a focal length of the second lens element, the third lens element and the fourth lens element combined is f234, a focal length of the fifth lens element is f5, and they satisfy the relation: −0.9<f234/f5<−0.05.
 14. The optical lens system with a wide field of view as claimed in claim 1, wherein a focal length of the first lens element, the second lens element and the third lens element combined is f123, the focal length of the fourth lens element is f4, and they satisfy the relation: −4.9<f123/f4<4.5.
 15. The optical lens system with a wide field of view as claimed in claim 1, wherein a focal length of the first lens element, the second lens element and the third lens element combined is f123, a focal length of the fourth lens element and the fifth lens element combined is f45, and they satisfy the relation: −5.1<f123/f45<3.5.
 16. The optical lens system with a wide field of view as claimed in claim 1, wherein a focal length of the first lens element is f1, a focal length of the second lens element, the third lens element, the fourth lens element and the fifth lens element combined is f2345, and they satisfy the relation: −2.5<f1/f2345<−1.2.
 17. The optical lens system with a wide field of view as claimed in claim 1, wherein an Abbe number of the second lens element is V2, an Abbe number of the third lens element is V3, and they satisfy the following relation: 29<V2−V3<42.
 18. The optical lens system with a wide field of view as claimed in claim 1, wherein an Abbe number of the fourth lens element is V4, an Abbe number of the fifth lens element is V5, and they satisfy the following relation: 29<V4−V5<42.
 19. The optical lens system with a wide field of view as claimed in claim 1, wherein a focal length of the optical lens system with a wide field of view is f, a distance from the object-side surface of the first lens element to an image plane along the optical axis is TL, and they satisfy the relation: 0.05<f/TL<0.4. 